+++ /dev/null
-use bitcoin::blockdata::script::{Script,Builder};
-use bitcoin::blockdata::opcodes;
-use bitcoin::blockdata::transaction::{TxIn,TxOut,OutPoint,Transaction};
-
-use bitcoin_hashes::{Hash, HashEngine};
-use bitcoin_hashes::sha256::Hash as Sha256;
-use bitcoin_hashes::ripemd160::Hash as Ripemd160;
-use bitcoin_hashes::hash160::Hash as Hash160;
-use bitcoin_hashes::sha256d::Hash as Sha256dHash;
-
-use ln::channelmanager::PaymentHash;
-
-use secp256k1::key::{PublicKey,SecretKey};
-use secp256k1::Secp256k1;
-use secp256k1;
-
-pub const HTLC_SUCCESS_TX_WEIGHT: u64 = 703;
-pub const HTLC_TIMEOUT_TX_WEIGHT: u64 = 663;
-
-// Various functions for key derivation and transaction creation for use within channels. Primarily
-// used in Channel and ChannelMonitor.
-
-pub fn build_commitment_secret(commitment_seed: [u8; 32], idx: u64) -> [u8; 32] {
- let mut res: [u8; 32] = commitment_seed;
- for i in 0..48 {
- let bitpos = 47 - i;
- if idx & (1 << bitpos) == (1 << bitpos) {
- res[bitpos / 8] ^= 1 << (bitpos & 7);
- res = Sha256::hash(&res).into_inner();
- }
- }
- res
-}
-
-pub fn derive_private_key<T: secp256k1::Signing>(secp_ctx: &Secp256k1<T>, per_commitment_point: &PublicKey, base_secret: &SecretKey) -> Result<SecretKey, secp256k1::Error> {
- let mut sha = Sha256::engine();
- sha.input(&per_commitment_point.serialize());
- sha.input(&PublicKey::from_secret_key(&secp_ctx, &base_secret).serialize());
- let res = Sha256::from_engine(sha).into_inner();
-
- let mut key = base_secret.clone();
- key.add_assign(&res)?;
- Ok(key)
-}
-
-pub fn derive_public_key<T: secp256k1::Signing>(secp_ctx: &Secp256k1<T>, per_commitment_point: &PublicKey, base_point: &PublicKey) -> Result<PublicKey, secp256k1::Error> {
- let mut sha = Sha256::engine();
- sha.input(&per_commitment_point.serialize());
- sha.input(&base_point.serialize());
- let res = Sha256::from_engine(sha).into_inner();
-
- let hashkey = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&res)?);
- base_point.combine(&hashkey)
-}
-
-/// Derives a revocation key from its constituent parts
-pub fn derive_private_revocation_key<T: secp256k1::Signing>(secp_ctx: &Secp256k1<T>, per_commitment_secret: &SecretKey, revocation_base_secret: &SecretKey) -> Result<SecretKey, secp256k1::Error> {
- let revocation_base_point = PublicKey::from_secret_key(&secp_ctx, &revocation_base_secret);
- let per_commitment_point = PublicKey::from_secret_key(&secp_ctx, &per_commitment_secret);
-
- let rev_append_commit_hash_key = {
- let mut sha = Sha256::engine();
- sha.input(&revocation_base_point.serialize());
- sha.input(&per_commitment_point.serialize());
-
- Sha256::from_engine(sha).into_inner()
- };
- let commit_append_rev_hash_key = {
- let mut sha = Sha256::engine();
- sha.input(&per_commitment_point.serialize());
- sha.input(&revocation_base_point.serialize());
-
- Sha256::from_engine(sha).into_inner()
- };
-
- let mut part_a = revocation_base_secret.clone();
- part_a.mul_assign(&rev_append_commit_hash_key)?;
- let mut part_b = per_commitment_secret.clone();
- part_b.mul_assign(&commit_append_rev_hash_key)?;
- part_a.add_assign(&part_b[..])?;
- Ok(part_a)
-}
-
-pub fn derive_public_revocation_key<T: secp256k1::Verification>(secp_ctx: &Secp256k1<T>, per_commitment_point: &PublicKey, revocation_base_point: &PublicKey) -> Result<PublicKey, secp256k1::Error> {
- let rev_append_commit_hash_key = {
- let mut sha = Sha256::engine();
- sha.input(&revocation_base_point.serialize());
- sha.input(&per_commitment_point.serialize());
-
- Sha256::from_engine(sha).into_inner()
- };
- let commit_append_rev_hash_key = {
- let mut sha = Sha256::engine();
- sha.input(&per_commitment_point.serialize());
- sha.input(&revocation_base_point.serialize());
-
- Sha256::from_engine(sha).into_inner()
- };
-
- let mut part_a = revocation_base_point.clone();
- part_a.mul_assign(&secp_ctx, &rev_append_commit_hash_key)?;
- let mut part_b = per_commitment_point.clone();
- part_b.mul_assign(&secp_ctx, &commit_append_rev_hash_key)?;
- part_a.combine(&part_b)
-}
-
-pub struct TxCreationKeys {
- pub per_commitment_point: PublicKey,
- pub revocation_key: PublicKey,
- pub a_htlc_key: PublicKey,
- pub b_htlc_key: PublicKey,
- pub a_delayed_payment_key: PublicKey,
- pub b_payment_key: PublicKey,
-}
-
-impl TxCreationKeys {
- pub fn new<T: secp256k1::Signing + secp256k1::Verification>(secp_ctx: &Secp256k1<T>, per_commitment_point: &PublicKey, a_delayed_payment_base: &PublicKey, a_htlc_base: &PublicKey, b_revocation_base: &PublicKey, b_payment_base: &PublicKey, b_htlc_base: &PublicKey) -> Result<TxCreationKeys, secp256k1::Error> {
- Ok(TxCreationKeys {
- per_commitment_point: per_commitment_point.clone(),
- revocation_key: derive_public_revocation_key(&secp_ctx, &per_commitment_point, &b_revocation_base)?,
- a_htlc_key: derive_public_key(&secp_ctx, &per_commitment_point, &a_htlc_base)?,
- b_htlc_key: derive_public_key(&secp_ctx, &per_commitment_point, &b_htlc_base)?,
- a_delayed_payment_key: derive_public_key(&secp_ctx, &per_commitment_point, &a_delayed_payment_base)?,
- b_payment_key: derive_public_key(&secp_ctx, &per_commitment_point, &b_payment_base)?,
- })
- }
-}
-
-/// Gets the "to_local" output redeemscript, ie the script which is time-locked or spendable by
-/// the revocation key
-pub fn get_revokeable_redeemscript(revocation_key: &PublicKey, to_self_delay: u16, delayed_payment_key: &PublicKey) -> Script {
- Builder::new().push_opcode(opcodes::all::OP_IF)
- .push_slice(&revocation_key.serialize())
- .push_opcode(opcodes::all::OP_ELSE)
- .push_int(to_self_delay as i64)
- .push_opcode(opcodes::all::OP_CSV)
- .push_opcode(opcodes::all::OP_DROP)
- .push_slice(&delayed_payment_key.serialize())
- .push_opcode(opcodes::all::OP_ENDIF)
- .push_opcode(opcodes::all::OP_CHECKSIG)
- .into_script()
-}
-
-#[derive(Clone, PartialEq)]
-pub struct HTLCOutputInCommitment {
- pub offered: bool,
- pub amount_msat: u64,
- pub cltv_expiry: u32,
- pub payment_hash: PaymentHash,
- pub transaction_output_index: Option<u32>,
-}
-
-#[inline]
-pub fn get_htlc_redeemscript_with_explicit_keys(htlc: &HTLCOutputInCommitment, a_htlc_key: &PublicKey, b_htlc_key: &PublicKey, revocation_key: &PublicKey) -> Script {
- let payment_hash160 = Ripemd160::hash(&htlc.payment_hash.0[..]).into_inner();
- if htlc.offered {
- Builder::new().push_opcode(opcodes::all::OP_DUP)
- .push_opcode(opcodes::all::OP_HASH160)
- .push_slice(&Hash160::hash(&revocation_key.serialize())[..])
- .push_opcode(opcodes::all::OP_EQUAL)
- .push_opcode(opcodes::all::OP_IF)
- .push_opcode(opcodes::all::OP_CHECKSIG)
- .push_opcode(opcodes::all::OP_ELSE)
- .push_slice(&b_htlc_key.serialize()[..])
- .push_opcode(opcodes::all::OP_SWAP)
- .push_opcode(opcodes::all::OP_SIZE)
- .push_int(32)
- .push_opcode(opcodes::all::OP_EQUAL)
- .push_opcode(opcodes::all::OP_NOTIF)
- .push_opcode(opcodes::all::OP_DROP)
- .push_int(2)
- .push_opcode(opcodes::all::OP_SWAP)
- .push_slice(&a_htlc_key.serialize()[..])
- .push_int(2)
- .push_opcode(opcodes::all::OP_CHECKMULTISIG)
- .push_opcode(opcodes::all::OP_ELSE)
- .push_opcode(opcodes::all::OP_HASH160)
- .push_slice(&payment_hash160)
- .push_opcode(opcodes::all::OP_EQUALVERIFY)
- .push_opcode(opcodes::all::OP_CHECKSIG)
- .push_opcode(opcodes::all::OP_ENDIF)
- .push_opcode(opcodes::all::OP_ENDIF)
- .into_script()
- } else {
- Builder::new().push_opcode(opcodes::all::OP_DUP)
- .push_opcode(opcodes::all::OP_HASH160)
- .push_slice(&Hash160::hash(&revocation_key.serialize())[..])
- .push_opcode(opcodes::all::OP_EQUAL)
- .push_opcode(opcodes::all::OP_IF)
- .push_opcode(opcodes::all::OP_CHECKSIG)
- .push_opcode(opcodes::all::OP_ELSE)
- .push_slice(&b_htlc_key.serialize()[..])
- .push_opcode(opcodes::all::OP_SWAP)
- .push_opcode(opcodes::all::OP_SIZE)
- .push_int(32)
- .push_opcode(opcodes::all::OP_EQUAL)
- .push_opcode(opcodes::all::OP_IF)
- .push_opcode(opcodes::all::OP_HASH160)
- .push_slice(&payment_hash160)
- .push_opcode(opcodes::all::OP_EQUALVERIFY)
- .push_int(2)
- .push_opcode(opcodes::all::OP_SWAP)
- .push_slice(&a_htlc_key.serialize()[..])
- .push_int(2)
- .push_opcode(opcodes::all::OP_CHECKMULTISIG)
- .push_opcode(opcodes::all::OP_ELSE)
- .push_opcode(opcodes::all::OP_DROP)
- .push_int(htlc.cltv_expiry as i64)
- .push_opcode(opcodes::all::OP_CLTV)
- .push_opcode(opcodes::all::OP_DROP)
- .push_opcode(opcodes::all::OP_CHECKSIG)
- .push_opcode(opcodes::all::OP_ENDIF)
- .push_opcode(opcodes::all::OP_ENDIF)
- .into_script()
- }
-}
-
-/// note here that 'a_revocation_key' is generated using b_revocation_basepoint and a's
-/// commitment secret. 'htlc' does *not* need to have its previous_output_index filled.
-#[inline]
-pub fn get_htlc_redeemscript(htlc: &HTLCOutputInCommitment, keys: &TxCreationKeys) -> Script {
- get_htlc_redeemscript_with_explicit_keys(htlc, &keys.a_htlc_key, &keys.b_htlc_key, &keys.revocation_key)
-}
-
-/// panics if htlc.transaction_output_index.is_none()!
-pub fn build_htlc_transaction(prev_hash: &Sha256dHash, feerate_per_kw: u64, to_self_delay: u16, htlc: &HTLCOutputInCommitment, a_delayed_payment_key: &PublicKey, revocation_key: &PublicKey) -> Transaction {
- let mut txins: Vec<TxIn> = Vec::new();
- txins.push(TxIn {
- previous_output: OutPoint {
- txid: prev_hash.clone(),
- vout: htlc.transaction_output_index.expect("Can't build an HTLC transaction for a dust output"),
- },
- script_sig: Script::new(),
- sequence: 0,
- witness: Vec::new(),
- });
-
- let total_fee = if htlc.offered {
- feerate_per_kw * HTLC_TIMEOUT_TX_WEIGHT / 1000
- } else {
- feerate_per_kw * HTLC_SUCCESS_TX_WEIGHT / 1000
- };
-
- let mut txouts: Vec<TxOut> = Vec::new();
- txouts.push(TxOut {
- script_pubkey: get_revokeable_redeemscript(revocation_key, to_self_delay, a_delayed_payment_key).to_v0_p2wsh(),
- value: htlc.amount_msat / 1000 - total_fee //TODO: BOLT 3 does not specify if we should add amount_msat before dividing or if we should divide by 1000 before subtracting (as we do here)
- });
-
- Transaction {
- version: 2,
- lock_time: if htlc.offered { htlc.cltv_expiry } else { 0 },
- input: txins,
- output: txouts,
- }
-}
projects / rust-lightning / blobdiff